Electric clock



Dec. 15, 1936.

c. BATEHOLTS 2,063,976

ELECTRIC CLOCK Filed Sept. 7, 1932 INVEN'TDRI I CLINTON EATEHULT Hi5ATTEENEY Patented Dec. 15, 1936 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to clock mechanisms of the type in which a trainof gears is driven by a synchronous motor connected to a source ofalternating current, and more particularly to means for assembling suchclocks.

The general object of the invention is to provide means which permitssuch mechanisms to be quickly and accurately assembled.

Another object of the invention is to provide means which permits suchmechanisms to be so assembled as to maintain the noise incident to theoperation thereof at a minimum.

For a clear understanding as to how the above and other objects areattained reference may be made to the accompanying drawing. In thisdrawing, however, the invention is shown merely in preferred form and byway of example, and obviously many changes and variations may be madetherein and in its mode of operation which 50 will still be comprisedwithin its spirit. It is, therefore, to be understood that the inventionis not limited to any specific form or embodiment, except insofar assuch limitations are specified in the claims.

Figure 1 is a perspective view of the back supporting plate with theclock mechanism and rotor pulled away to more clearly show the assembly.

Figure 2 is a longitudinal view partially in section of the main drivingshaft and associated parts.

Figure 3 is an exploded perspective view of the rotor and the clockmechanism with the bearing plates omitted, and

Figure 4 is a partial plan view of the back supporting plate showing theposition of the rotor and the pole pieces.

Referring to the drawing the structure comprises three spaced bearingplates ill, I I, and I2.

0 The plate i2 which also serves as the back supporting plate isdesirably moulded from bakelite or other suitable moulding compound andhas a plurality of lugs l3 extending therefrom to which the face plateof the clock is secured. The 5 plates l0 and II are desirably made fromsheet metal and are connected together in spaced relation by four hollowbinding posts i4. As shown more clearly by Figure 1, the binding postsl4 are adapted and arrangedto fit over the ends of 0 four supportingstuds I5, l6, I1, and I8 which are desirably set in place during themoulding of the back supporting plate l2. The center bearing plate H isheld in spaced relation from the back supporting plate i2 by-means ofsleeves 5 I9 and which are moulded about the binding posts l5 and i6respectively and by metallic sleeves 2i and 22 which fit over thebinding posts I! and I8 respectively.

The synchronous motor comprises a rotor 23 and pole pieces 24 and 25.The rotor 23 is rigidly 5 mounted on a bushing 26 which, in turn, isrigidly mounted on a main driving or rotor shaft 21, journaled inbearings 28 and 29, and the outer periphery of the rotor 23 comprises aplurality of regularly spaced radial projections 30. 10 The pole pieces24 and are secured, as by a plurality of spun rivets 35, to two shouldermembers 3| and 32 which are moulded integral with the back supportingplate l2, and the faces of the pole pieces also comprise a plurality ofreg- 15 ularly spaced projections 33. The pole pieces are so positionedon the shoulder members 3| and 32 that the projection 33 on the polepieces are adjacent the projections on the rotor and a horizontal lineb-b drawn across the top of the 20 pole pieces is below a parallelhorizontal line H drawn through the axis of rotation of the rotor.

A core 34 is connected across the pole pieces 24 and 25, as by aplurality of spun rivets 35a, to 25 complete the magnetic circuit, andto prevent the occurrence of heat-creating eddy currents in the magneticstructure the armature and pole pieces are laminated. A coil 36 which isadapted and arranged to be connected to a suitable source of alternatingcurrent by conductors 31 and 38 is wound on core 34 and acts to energizethe pole pieces 24 and 25 when traversed by current. The alternatingcurrent passing through the coil 36 produces a magnetic flux in core 34,the flux circuit of which is completed through the poles 24 and 25 andthat portion of the rotor 23 intermediate the poles 24 and 25. This fluxvaries in density and direction in accordance with the current flowthrough the coil 36. The projec- 40 tions 30 on the periphery of therotor 23 are successively attracted toward the projections 33 on thestationary pole pieces 24 and 25 after the rotor has been manuallystarted. The operation of motors of this type is well known in the artand further explanation is not believed to be necessary. By mounting thepole pieces 24 and 25 as shown a constant downward pull is created onthe rotor 23. This downward pull on the rotor maintains the rotor shaft21 in contact 5 with the lower portions of the bearings 28 and 29 and asa result the shaft does not have a tendency to float in the bearings.The pole pieces are preferably mounted below the rotor because. when inthis position the attraction exerted by the pole pieces is augmented bygravity. A fly wheel 39 is loosely mounted on the bushing 26intermediate collar 40 and a shoulder on bushing 26 to maintain uniformthe rotation or rotor 23. This feature is also old in the art andfurther explanation is not believed to be necessary.

The bearings 28 and 29 in which the shaft 21 is journaled are preferablymade from a cellulosic compound such as that sold under the trade nameof Lumarith since such bearings have been found to be noiseless and topossess good wearing qualities. While a cellulosic compound is preferredas the bearing material other materials such as Bakelite or othersuitable phenol condensation products may be used. The bearing 28 ispreferably set in the back plate i2 during the moulding of the plate. Itis to be understood, however, that this method of placing the bearing 28in the plate I2 is preferred merely from a manufacturing standpoint andthat the bearing may be placed in a suitable opening after plate l2 hasbeen moulded. The bearing 29 comprises a shoulder portion which abutsthe plate II and a hub portion 4| which extends through the plate.

As the rotor 23 rotates under the influence of the varying magneticfield it drives the main driving or rotor shaft 21. As the shaft 21rotates it drives a sleeve 42 and a worm gear 43 fixedly mountedthereon. The worm gear 43 is in mesh with and drives a gear 44 which isfixedly mounted on one end of a shaft 45 journaled on bearings (notshown) carried by the plate I0. As the shaft 45 rotates it drives a wormgear 46 fixedly mounted thereon. The worm gear 46 is in mesh with anddrives a gear 41 which is fixedly mounted on one end of a shaft 48journaled in brackets 48a (one of which is shown) carried by the plateAs the shaft 48 rotates it drives a worm gear 49 which is fixedlymounted on the other end of the shaft. The worm gear 48 is in mesh withand drives a gear 50 mounted on one end of a hollow shaft 5|. One end ofshaft 5| is journaled on the hub portion 4| of the bushing 28 and thecentral portion of the shaft is iournaled in bushing 52. Bushing 52 isjournaled in bushing 53 which in turn is fixedly mounted in bearingplate i0. As shaft 5| rotates it drives a minute hand 54 which issecured to the other end of the shaft and a gear 55 which is fixedlysecured to the central portion of the shaft behind the plate The gear 55is in mesh with and drives gear 56 which is fixedly mounted on one endof shaft 51. As the shaft 51 rotates it drives a gear 58 which isfixedly secured to the other end thereof. The gear 58 is in mesh withand drives a gear 58 which is fixedly mounted on one end of the bushing52. As the bushing 52 rotates in bushing 53 it turns the hour hand 50which is fixedly secured to the other end thereof.

A reset gear 5| (Fig. 1) is mounted on a shaft 52 and is normally heldout of mesh with gear 56 by spring 63. The shaft 52 is journaled inplates i0 and ii and extends through an aperture 65 in the back platei2. To permit the minute and the hour hands 54 and 60 respectively to bereset without turning the main driving or rotor shaft 21, the gear 58 isfrictionally mounted on shaft 5| intermediate the spring 64 and thecollar 65 (Fig. 2). To reset the hands the shaft 62 is pulled outwardlyuntil the gear 6| is in mesh with the gear 56. The shaft 56 is thenturned thereby rotating gears 56 and 58. As the gears 56 and 58 rotatethey rotat gears 55 and 59 respectively. As the gears 55 and 59 rotatethey drive the bushings 5| and 52 on which the minute hand 54 and thehour hand 58 are respectively mounted. The friction developed by thespring 64 against the gear 50 is insumcient to permit the gear 55 drivethe worm gear 48 and as a result the gear 50 slips on shaft 5| but issufficient to permit the worm gear 4! drive the gear 5".

An oil saturated felt washer 55 is mounted on shaft 25 adjacent thebearing 24 to lubricate the bearing during operation.

The feature of moulding the back supporting plate and providing it witha plurality of lugs on which the motor and the clock mechanism may bemounted simplifies the construction of the clock and permits the clockto be rapidly assembled without danger of the rotor shaft bearings beingout of alignment.

While the pole pieces are preferably mounted so that they create adownward pull it is to be understood that favorable results may beobtained by mounting the pole pieces in other positions with respect tothe rotor. For example the pole pieces may be mounted so as to create aconstant upward pull or a constant side pull on the rotor. The essentialfeature in all cases being that the pole pieces shall be mounted on oneside of a straight line drawn through the axis of rotation so as tocreate a steady pull on one side of the outer periphery of the rotor.

I claim:

1. In an electric clock having a gear train assembled in a frame, amoulded back supporting plate having lugs extending therefrom forsupporting said frame, a main drive shaft for d11ving said train, oneend of said shaft being journaled in said back supporting plate, and theother end of said shaft being journaled in said frame andelectro-magnetlc means for rotating said shaft.

2. In an electric clock having a gear train assembled in a frame, thecombination of a back supporting plate having lugs extending therefromfor supporting said frame, a main drive shaft for driving said train,one end of said shaft being journaled in said plate and the other end ofsaid shaft being journaled in said frame, a rotor mounted on said shaftand magnetic pole pieces secured directly to said plate adjacent theouter periphery of said rotor.

3. In an electric clock having a gear train assembled in a frame, thecombination of a back supporting plate having lugs extending therefromfor supporting said gear frame, a main drive shaft for driving saidtrain, one end of said shaft being journaled in said plate and the otherend of said shaft being journaled in said frame, a rotor mounted on saidshaft and magnetic pole pieces secured directly to said plate adJacentthe outer periphery of said rotor and on one side of a straight linedrawn through the axis of rotation of said rotor.

4. In an electric clock having a gear train assembled in a frame, a backsupporting plate having lugs extending therefrom for supporting saidframe, a non-metallic bearing carried by said plate, a non-metallicbearing carried by said frame, a main shaft journaled in said bearingsand adapted to drive said train and means responsive to an electricalimpulse for rotating said shaft.

5. In an electric clock having a gear train assembled in a frame, a backsupporting plate having lugs extending therefrom for supporting saidaooaova' 3 frame, a non-metallic bearing carried by said plate, anon-metallic bearing carried by said frame, a main shaft journaled insaid bearings and adapted to drive said train, a rotor mounted on saidshaft and means responsive to an elec trical impulse for rotating saidrotor to drive said shaft.

6. In an electric clock having a gear train assembled in a frame, polepieces, a back supportin: plate having lugs extending therefrom forsupporting saidtrame and shoulders extending therefrom for supportingsaid pole pieces, a nonmetallic bearing carried by said plate. a.nonmetaliic bearing carried by said frame, a main shaft journaled insaid bearings and adapted to drive said train, and a rotor mounted onsaid shaft adjacent said pole pieces.

CLINTON BATEHOLTS.

